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Prenatal Diagnosis and Screening for Aneuploidy
Published in Vincenzo Berghella, Obstetric Evidence Based Guidelines, 2022
Sarah Harris, Angie Jelin, Neeta Vora
For the purpose of genetic testing, amniocentesis is typically completed between 15 and 20 weeks of pregnancy. The procedure is performed using a 22-guage needle and direct ultrasound guidance to obtain a sample of amniotic fluid.
Assessment of fetal genetic disorders
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Teresa Martino, J. Pratt Rossiter, Karin J. Blakemore
The use of amniocentesis to prenatally detect chromosomal abnormalities was first reported in 1967 (42). Since that time, amniocentesis has become a widely accepted method for prenatal diagnosis of chromosomal abnormalities, inherited diseases, and some congenital infections. Despite about experience of three decades with midtrimester amniocentesis, determination of the risk of procedure-related pregnancy loss has been difficult. Risk estimates have ranged from 0.5% to 1% in large, prospective, multicenter trials (43–45). Total loss rates following invasive procedures are more readily accessible, encompassing the “background” fetal loss rate plus the procedure-related loss rate. A systematic review by Mujezinovic et al. showed a pooled pregnancy loss within 14 days after amniocentesis of 0.6% and rising to 0.9% before 24 weeks of gestation. The total pregnancy loss rate was 1.9% (46).
Antenatal screening
Published in Alison Edwards, Antenatal Midwifery Skills, 2020
Amniocentesis – from 15 weeks. Amniotic fluid is extracted via the mother's abdomen and sent for DNA analysis. Identifies any chromosomal abnormalities (e.g. Edwards's, Turner's or Down's syndrome). Risk of miscarriage is around 1%.
Noninvasive prenatal screening in southeast China: clinical application and accuracy evaluation
Published in Expert Review of Molecular Diagnostics, 2022
Li Wen, Jiye Gao, Leilei Huang, Dongmei Li, Guansheng Zhong
Further diagnostic confirmation showed that common trisomy was found in 213 (72.0%) cases (T21: 170; T18: 37; T13: 6), including three cases of mosaic T21 and four cases of robertsonian translocation [46,XN,der(14;21)(q10;q10), +21]. The PPV for T21, T18, and T13 were 83.7%, 72.5%, and 14.3%, respectively. Table 2 presents the diagnostic results of amniocentesis based on different kinds of detecting methods. After professional genetic consultation, all of the pregnant women with common trisomy selected to terminate the pregnancy. Among which, there were two cases (one in T21 and one in T13) having fetus born, due to their rejection of amniocentesis, and confirmed after childbirth in final. Three cases of mosaic T21 with mosaicism level of 20%, 41%, and 58% had the same choice as cases with full T21 fetus. On the other hand, pregnancies with normal karyotype were believed to deliver without abnormalities, excepting for some loss of follow-up. The prenatal decision and follow-up results are summarized in Table 3. Furthermore, 12 cases with incidental findings were recognized by karyotyping and CMA detection technologies, while firstly defined as NIPS-positive in T21/T18/T13 (Table 4). Of these, 25% involved the same chromosomes screened by NIPS with abnormal Z-score (ranging from 4.907 to 17.334), and 75% referred to variations in other chromosomes.
Identification and management of fetal anemia due to hemolytic disease
Published in Expert Review of Hematology, 2022
Renske M. van ’t Oever, Carolien Zwiers, Derek de Winter, Masja de Haas, Dick Oepkes, Enrico Lopriore, E.J.(Joanne) Verweij
If the paternal phenotype is heterozygous, or if there is uncertainty about paternity, the phenotype of the fetus should be established. This used to be an invasive procedure where fetal material was collected by amniocentesis or chorionic villi sampling. For D, C, c, E and K this can be done noninvasively by amplifying cell-free fetal DNA (cffDNA) from maternal plasma using various PCR-based assays [46]. The sensitivity and specificity of these noninvasive techniques have been extensively studied and gives sensitivity levels of 99–99.9% and specificity of 95% or higher [47]. The noninvasiveness of these techniques reduced miscarriage rates and mild-to-severe hemolysis conversions associated with more invasive techniques [48].
Relationship between second-trimester amniotic fluid and plasma levels of angiopoietin-2 and thrombomodulin with adverse pregnancy outcome
Published in Journal of Obstetrics and Gynaecology, 2022
Cem Yener, Füsun Varol, Cihan Inan, Havva Sütcü, Sinan Ateş, Cenk Sayin
This prospective multiparametric pilot study was conducted at the Perinatology Unit of Trakya University in a population underwent genetic amniocentesis. The study was approved by the local institutional ethics committee (protocol number: 2018/187). Initially, 127 genetic amniocentesis between 16 and 24 weeks were included in the study. Amniocentesis was performed due to various indications: advanced maternal age (n = 11), abnormal first-trimester (n = 18) or second-trimester screening test (n = 77), abnormal ultrasonography findings (n = 16), history of genetic disorder (n = 4) and high risk in non-invasive prenatal test (NIPT) (n = 1). During the final data evaluation, 39 were excluded with various reasons. Our exclusion criteria were: a missed abortion, foetal chromosomal anomalies, major foetal structural anomalies, preterm premature rupture of the membranes, multifetal gestations, pregnancies with diabetes mellitus, chronic hypertension, connective tissue disorders and a body mass index less than 18 or more than 28. A total of 88 singleton pregnancies were included in the study after excluding 39 cases. We divided patients into three groups as follows: 12 subsequently developed FGR in group 1, 11 complicated with PE ((mild PE (n = 7), severe PE (n = 4)) in group 2, 65 women delivered beyond >37th week with an uncomplicated outcome as the controls in group 3. Peripheral blood samples (5 cm3) taken from the patients during the procedure were centrifugated at 4000/min for 10 minutes. Both AF and plasma aliquots were stored at –80 °C until assayed. We followed up on the patients until delivery and the pregnancy outcomes were recorded.